Apparatus for forming an edge reinforced non-woven web



March 13, 1962 w. H. BURGER APPARATUS FOR FORMING AN EDGE REINFORED NON-WOVEN WEB Filed Feb. 6, 1958 2 Sheets-Sheet 1 llll Il llll :Irun

March 13, 1962 w. H. BURGER 3,025,196

APPARATUS FOR EORMING AN EDGE REINEORCED NoN-WOVEN WEB Filed Feb. 6, 1958 2 Sheets-Sheet 2 ADHES/ VE ite States te The present invention relates to an improvement in apparatus for forming non-woven thread and web structures in a continuous manner, and is particularly useful in apparatus such as disclosed in patent application Serial No. 476,027, liled December 17, 1954, by Harland W. Hirschy, now Patent 2,841,202, for An Apparatus for Forming Multi-Ply Web Product, and is assigned to the assignee of that application.

In the manufacture of non-woven multi-ply materials as disclosed in the aforesaid application, it has been discovered that upon cutting of the superposed medium or ply, particularly when that medium comprises certain types of threads or fibers, the end portions of the medium may tend to spring back and curl as the result of either release of tension in the medium or a natural tendency of the medium to curl. The release of tension may result not only in a curling of the ends of the material, but in certain instances also may result in considerable distortion of the web through displacement of the subposed medium from its original precise placement. Since there is initially only a very light bond between the superposed and subposed media, there also is a tendency to displacement of the superposed medium merely from air resistance to travel of the web.

This invention provides means whereby the tendency to curl is overcome, and contraction and displacement of the superposed threads upon severance thereof is substantially eliminated.

The particular objects and efforts of the invention will be apparent in greater detail from the following description and the accompanying drawings, in which:

FIGURE l is a generally schematic drawing of a crosslaying machine incorporating the present invention, and

FIGURE 2 is an enlarged partial cross-section, taken on the line of 2-2 of FIGURE 1, showing in detail particulars of the present invention.

FIG. 3 is a View, partially in vertical section and partially schematic, illustrating the manner in which adhesively coated threads are laid down on each side of the rotary cutter of FIGS. 1 and 2.

Referring to FIGURE 1, which is simil-ar to FIGURE 8 of the aforesaid application Serial No. 476,027, a sheet 81 which may be of non-woven fabric, or other sheet material may be received under a roll 82 whereupon it is guided onto the surface of a moving belt 83 by means of a roll 84. As the sheet 81 and belt 83 move to the right as seen in FIGURE 1, the sheet is overlaid with a pattern of longitudinal threads 86. Threads 86 are constantly supplied from a creel 87 containing a plurality of series of such threads which pass through a plurality of gulide means S8 arranged to direct the threads over a first guide bar 89 and about a second horizontally disposed guide bar 91. The threads 86 then pass over a comb array 92, following which they are given a coat of adhesive from an applicator roll 93 in contact with the threads. A suitable adhesive such as a thermoplastic resinous composition is applied to the surface of the applicator roll 93 from a roll 94 in Contact therewith.

After the threads 86 have received a coating of adhesive, the thread reinforced web and the belt 83 carrying the web are guided about a stationary cylindrical mandrel 96 so as to form thereon a rst helix, as shown. The belt 83, of course, is continuously pulled about Patented Mar. 13, 1962 stationary mandrel 96 by conventional means not shown. Referring also to FIGURE 2, mandrel 96 has a helical band or spline 129 mounted thereon, to serve as a guide for belt S3.

Mandrel 96 is substantially coaxial with a rotating carrier or disc 97 which applies threads to the moving web in a direction normal to the direction of the previously applied threads 36. In other words, carrier 97 is arranged to wrap additional threads in the form of helices at substantial angles to the helices formed by the previously disposed threads 36 as those threads pass about the mandrel. The points of Contact as shown form equally spaced points on a right circular section of the mandrel, but the line or angle of intersection may be varied as desired within a considerable range depending on the manner in which the threads are received on the supporting surface.

Carrier 97 on each side supports a plurality of circumferentially spaced cones 98 of thread, which feed threads 99 centrally of carrier disc 97 and over an annular series of guide means 101 onto the surface of the moving web of threads 86. Just before or at the time belt 83 is removed from mandrel 96, a slitter 102 engages the web to sever the cross threads 99 parallel to the marginal edge of the moving web. The resulting thread-reinforced product 119 is then separated from belt 33 and the belt passes over a series of rollers, including rollers 193 and lll-i before returning to the inlet end of the machine. The thread-reinforced product then may be passed about a heated roller 105 in contact with a heat-resistant roller 197 to cause the adhesive applied to threads S6 to become more plastic and to flow about the junction of threads and 99.

After leaving the surface of roller 1117 the completed product may be conveyed as by roller 108 to a slitting means 109 where the web 110 is cut to desired width and the slit web strips may then be wound about a windup reel 111 by a pair of winding rolls 112 and 113.

Under normal conditions of operation there results a substantial amount of tension in threads 99 as they are applied to underlying threads 86. When threads 99 are cut by slitter 102, the tension upon the threads is re` leased, whereupon they tend to spring back to their original unstretched condition, with resultant lateral dis` tortion of the web. Since the various threads 99 coming from the numerous cones 98 have differing tensile characteristics, there is considerable variation in the degree of distortion caused by the various threads 99 as they relax upon being cut by cutter 162. The result is a -completed web lacking uniformity in width and appear- ,when in an unrestricted condition and this tendencyis particularly evident when the threads have just been unwound from spools and just released from a stretched condi-tion. Consequently, upon threads 99 being cut by cutter 192, there is a marked tendency for the ends of the threads to curl or lie back over the adjacent edge of the web 11d. This tendency to curl will be approximately proportioned to the amount by which threads 99 extend beyond the marginal ones of longitudinal threads S6, upon the cross threads being cut by cutter 102. This curling may be accentuated by air resistance to web travel.

It will be clear that sheet 81 may be omitted `from the product, in which case threads 86 will be supported directly by belt 83. lf sheet 81 is included, it may under certain conditions serve as the support for threads 86, in which case belt 83 may be eliminated.

The improvement of this invention lies in the provision of means whereby the tendency toward weakening and distortion of the finished web, and uncontrolled curl of the ends of the cross threads, are materially reduced or eliminated in a most economical fashion.

Referring to FIGURES 1 and 3, specifically this invention includes a supply of threads such as spools 35 and 36 from which threads 37 and 38 are fed through an adhesive applicator 39. Applicator 39 may be of -any of a number of conventional types, being here illustrated as a -tank with orifices 40 and 41 through which threads 37 and 38 may enter and 4leave the adhesive tank, receiving a predetermined application of adhesive. The threads then pass onto the moving web 110 subsequent to the application of cross laid threads 99 and prior to the cutting of the cross laid threads by cutter 102.

Threads 37 and 38 are lapplied to opposite sides of and preferably close to the longitudinal line along which cutter 102 will sever cross threads 99. The nearer threads 37 and 38 are applied to the longitudinal line, the greater will be their effectiveness in restraining the curl of cross threads 99 previously referred to.

The adhesive applied to threads 37 and 38 by applicator 39 is selected to be of a character such that upon application of the threads to the moving web there will be a substantial adhesion of threads 37 and 38 to cross threads 99 and also to the moving belt 83 or sheet 81 (as the case may be) immediately underlying longitudinal threads 86. There is thus a substantially direct tacking of cross threads 99 to the underlying sheet 81 or belt 83,

thus greatly restricting or eliminating contract-ion of threads 99 upon being cut by the cutter 102, and also eliminating curling of the ends of threads 99.

yDepending upon the precise nature of the cross threads 99, the set of the finished web 110 may be sufiiciently permanent after even a short time interval, and particularly after the heating and adhesive fixation by rollers 106 and 107, so that even though threads 37 and 38 are trimmed away by a subsequent trimming operation such as slitting means `109, no material distortion of the web or curling of the new ends of threads 99 will result. If the contrary is true it will be desirable to initially place hold-down threads 37 and 38 upon the web so that when the slitting operation occurs these threads will not be cut away. In such situation, and in an obvious fashion, it will be desirable to position additional hold-down threads on the web 110 internally of the side margins, to hold down the additional ends of threads 99 which are formed upon slitting the web into strips by means 109.

It will be apparent to those skilled yin the art that for threads 37 and 38 there could be substituted narrow tapes of any suitable material. Also, threads 37 and 38 could be applied -to the web by means of pressure-sensitive or thermo-sensitive adhesive incorporated in the threads, with the use of conventional pressure or heating means, thus eliminating the need for adhesive applicator 39. It is also clear that instead of trimming away threads 37 and 38 after the web has acquired a permanent set, it may be desirable to strip these threads off the web, which presents no problem if the adhesive yapplied to threads 37 and 38 is properly selected. Alternatively, the ends of threads 99 extending beyond threads 37 and 38 may be folded back upon threads 99 and suitably adhered lin place, thus forming a neat selvage edge.

In certain applications the marginal holdxlown means may satisfactorily comprise a non-adhesive endless thread or tape, which merely by tension therein holds down the ends of threads 99 as they are cut and the web is heat treated. This tape or thread will serve to prevent distortion and curl of the cross laid members due to windage and other causes during the slitting operation.

Other various modifications of the invention as above described will readily present themselves to those familiar to the art. Accordingly, it is to be understood that no CII limitation on the invention is intended except as specifically set forth in the claims.

What is claimed is:

l. In an apparatus for forming a continuous web product, the apparatus comprising a mandrel, means for carrying a first elongated medium at least one helical turn on said mandrel, a rotatable carrier mounted substantially coaxially with said mandrel, supply means for a second elongated medium mounted on said carrier, means for guiding said second medium over said first medium while the i'st medium is being carried on said mandrel, the second medium being applied in the form of a helix at a substantial angle to the long dimension of the first medium in the regions of intersection of said media, and means for cutting said second medium transversely of its long dimension after it has been applied to the first medium, the improvement comprising means for superposing a third elongated medium over said second medium in superposed relation, said third medium being applied after said second medium is applied over the first medium and prior to the cutting of said second medium, said third medium being applied transversely of the long dimension of the second medium and substantially parallel to the long dimension of the first medium and said third medium being applied adjacent the line along which said cutting means cuts the second medium.

2. Apparatus Iaccording to claim l, in which the means for superposing the third medium includes means for applying adhesive thereto to adhere the third medium to the second medium and to the me-ans for carrying the first medium on said mandrel.

3. Apparatus according to claim 2, in which said means for superposing a third medium comprises means for superposing a thread on each side of the line along which the cutting means cuts the second medium.

4. Apparatus according to claim l, in which said means for superposing a third medium comprises means for superposing a thread on each side of the line along which the cutting means cuts the second medium.

5. Apparatus for forming a continuous web product comprising a mandrel, supporting means including a flexible endless belt having at least one helical turn on said mandrel, means for depositing a first elongated medium on said supporting means to be carried about said mandrel, a rotatable carrier mounted substantially coaxially with said mandrel, supply means for a second elongated medium mounted on said carrier, means for guiding said second medium over said first medium while the first medium is being carried on said mandrel by the supporting means, the second medium Abeing applied in the form of a helix at a substantial angle to the long dimension of the first medium in the regions of intersection of said media, means for cutting said second medium transversely of its long dimension after it has been applied to the first medium, and means for superposing a third elongated medium over said second medium in superposed relation, said .third medium being applied after said sec ond medium is applied over the first medium and prior to the cutting of said second medium, said third medium being applied transversely of the long dimension of the second medium and substantially parallel to the long dimension of the first medium and said third medium being applied adjacent the line along which said cutting means cuts the second medium.

6. Apparatus according to claim 5, in which the means for superposing the third medium includes means for applying adhesive to said third medium to adhere the third medium to the second medium and to said supporting means.

7. Apparatus according to claim i6, in which said means for superposing a third medium comprises means for superposing a thread on each side of the line along which said cutting means cuts the second medium.

8. Apparatus according to claim 5, in which said means for superposing a third medium comprises, means for superposing a thread on each side of the line along which said cutting means cuts the second medium.

References Cited in the file of this patent UNITED STATES PATENTS Builey Nov. 25, 1919 

1. IN AN APPARATUS FOR FORMING A CONTINUOUS WEB PRODUCT, THE APPARATUS COMPRISING A MANDREL, MEANS FOR CARRYING A FIRST ELONGATED MEDIUM AT LEAST ONE HELICAL TURN ON SAID MANDREL, A ROTATABLE CARRIER MOUNTED SUBSTANTIALLY COAXIALLY WITH SAID MANDREL, SUPPLY MEANS FOR A SECOND ELONGATED MEDIUM MOUNTED ON SAID CARRIER, MEANS FOR GUIDING SAID SECOND MEDIUM OVER SAID FIRST MEDIUM WHILE THE FIRST MEDIUM IS BEING CARRIED ON SAID MANDREL, THE SECOND MEDIUM BEING APPLIED IN THE FROM OF A HELIX AT A SUBSTANTIAL ANGLE TO THE LONG DIMENSION OF THE FIRST MEDIUM IN THE REGIONS OF INTERSECTION OF SAID MEDIA, AND MEANS FOR CUTTING SAID SECOND MEDIUM TRANSVERSELY OF ITS LONG DIMENSION AFTER IT HAS BEEN APPLIED TO THE FIRST MEDIUM, THE IMPROVEMENT COMPRISING MEANS FOR SUPERPOSING A THIRD ELEONGATED MEDIUM OVER SAID FIRST MEDIUM IN SUPERPOSED RELATION, SAID THIRD MEDIUM BEING APPLIED AFTER SAID SECOND MEDIUM IS APPLIED OVER THE FIRST MEDIUM AND PRIOR TO THE CUTTING OF SAID SECOND MEDIUM, SAID THIRD MEDIUM BEING APPLIED TRANSVERSELY OF THE LONG DIMENSION OF THE SECOND MEDIUM AND SUBSTANTIALLY PARALLEL TO THE LONG DIMENSION OF THE FIRST MEDIUM AND SAID THIRD MEDIUM BEING APPLIED ADJACENT THE LINE ALONG WHICH SAID CUTTING MEANS CUTS THE SECOND MEDIUM. 